Movable access ramp for vehicles

ABSTRACT

A foldable ramp for loading and unloading a roll on-roll off type cargo ship and consisting of three pivotally interconnected sections the innermost one of which is pivoted with its inboard end to the ship for being lowerable and extendable onto a wharf by ramp handling cables and winches provided on the ship. The two outboard sections of the ramp are connected by ropes and sheaves to king-posts provided on the ship for automatically extending said sections while lowering the innermost ramp section through gravity.

United States Patent 11 1 Kum rma 51 Nov. 12, 1974 154] LE ACCESS RAMPFOR VEHICLES 2,641,785 6/1953 P1115 14/71 [75] Inventor: HenriKummerman, Geneva,

sw'lzcrllmd 3,468,280 9/1969 Williams 14 71 x 73 M 3,580,404 5/1971Moser.............. 14/71 x l I Wgncg fgg g g gggg S A 3,687,308 8/1972Apelstrand 14/71 x 3,747,354 7/1973 Macomber 61/48 I22] Filed: June 21,1973 121] App]. No.: 372,051

[30] Foreign Application Priority Data June 28, 1972 France 72.23373 May29, 1973 France 73.19511 [52] US. Cl. 14/71, 61/48, 214/15 R [51] Int.Cl. 865g 11/00 [58] Field of Search 14/71, 1, 7,17, 37; 214/15 R; 61/48[56] References Cited UNITED STATES PATENTS 2,556,175 (7/1951 Frost 14/12,617.131 ll/l952 Harris ,.14/71 Primary Examiner-Nile C.-Byers, Jr.Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin [57]ABSTRACT A foldable ramp for loading and unloading a roll onroll offtype cargo ship and consisting of three pivotally interconnectedsections the innermost one of which is pivoted with its inboard end tothe ship for being lowerable and extendable onto a wharf by ramphandling cables and winches provided on the ship. The two outboardsections of the ramp are connected by ropes and sheaves to king-postsprovided on the ship for automatically extending said sections whilelowering the innermost ramp section through gravity.

30 Claims, 20 Drawing Figures PATENTEDNUV 12 I974 SHEET [12 HF 11PATENTEDNUV 12 IBM sum on or 11 PATENTED Nov 12 I974 SHEET 05 0F 11PMENTEHMJV 1 2 I974 sum 06 or 11 PATENTED NOV 12 I974 SHEET PATENTED NEW12 I974 sum as or 11 PATENTEDunv 12 I974 sum 09 0F 11 PATENTEBHUHQIQM3346860 SHEET 10 0F 11 MOVABLE ACCESS RAMP FOR VEHICLES The presentinvention relates generally and is essentially directed to a movabledevice forming an access ramp or like gangway, horse or bridge meansadapted to provide a communication, passage, conveyance, transhipment orlike means between on the one hand any vehicle in particular of land ormarine character such as for instance a ship, boat or like floatingvessel and on the other hand an outside loading or unloading area orplatform such as a quay, pier, wharf, bank, shore or beach or yetanother vehicle as well as the various applications and uses resultingfrom implementing same and the systems, arrangements, assemblies,appliances, equipments and installations provided with such devices.

There are already known in particular in naval or marine applications,transport or cargo ships of the roll on-roll off type for conveying forinstance wheeled vehicles and in particular automotive or motor vehiclesor various goods and products. In the case of automotive vehicles, theshipping and unshipping thereof are effected by their own self-containedor independent propulsion or drive means by rolling individually orseparately and directly on a movable access ramp interconnecting theship (and more specifically the loading deck or flooring thereof) andthe quay or the like. In the case of general cargo, such a ramp is alsoused directly by automotive handling carriages, trucks or like carts orwheeled cargo-handling gears running on said ramp in a shuttle-likemanner enabling them to have direct access to the ship and to come backto the quay for loading or shipping and unloading or unshipping goodsand like cargoes. For this purpose, the ship is provided either aft orastern, or afore at the bow, or yet sidewise, with at least one largeramp of the kind pivotally connected with its inboard end to the shipfor swinging vertically so as to be liftable or raisable upwards to asubstantially inoperative upstanding position in a stowed or lashedcondition on the ship during its sea trip and lowerable in operativeworking position to bear onto the quay with its opposite, i.e. outboardend. As the ship is generally moored or secured along the quay berth inparallel relation thereto, said ramp, when it is located astern i.e. atthe rear end of the ship, is generally positioned slantwise in itslowered working condition with respect to the longitudinal centralvertical plane of the ship so that the longitudinal direction of theramp is at an angle of about 45 with respect to thelongitudinal-direction of the ship. Such a ramp thus enables variouskinds of wheeled vehicles to be taken aboard the ship for instance fromquays which are not fitted up or suited for such a use.

To enable the ship to use various kinds of quays while retaining anacceptable slope with respect to the horizontal direction for thepassage of wheeled vehicles, said ramp is required to be long enough andfor this ground it is necessary that the ramp may be folded verticallyback against the planking or structure of the ship so as not to offer atoo strong hold to the wind when the ship is at sea or'an excessiveheight likely to affect the stability of the ship.

For example, from the U.S. Pat. No. 3,687,308 is already known such aramp consisting of three successive sections pivotally interconnected toeach other, respectively, in the longitudinal direction, the innermostend or inboard section being pivoted to the ship in particular at thelevel of any opening thereof for example at a cargo port provided at oneof its ends or laterally in the side of the ship whereas the outer endor outboard section serves as a bearing or supporting flap member ontothe quay and is pivotally connected with an intermediate point thereofto the corresponding outer end portion of the intermediate section. Inthis known arrangement, the intermediate and outermost sections may befolded back together by being laid downwards against the bottom portionof the innermost or inboard section alongside thereof in a substantiallyupward raised or vertical position and both opposite side frame membersor like girders or spars of the inboard section are extended outwardsthrough a pair of booms or armlike beams extending beyond the vehiclerunway carried therebetween and on either side of and along theintermediate section so as to bear in the lowered and extended workingcondition onto a pair of sidewise outwards projecting supports providedon the intermediate section on either side thereof, through the mediumof a pair of longitudinal lower levers pivotally connected to the sideframe members so that said levers may be swung in a vertical plane to anadjustable relative angular position by pressure fluid operated ram-typeactuators or like power means. This arrangement enables to adjust theangle between the outboard and intermediate sections in the lowered andextended working state. The innermost or inboard section is secured withan intermediate point of one or each side frame member thereof andadjacent to its pivotal connection with the intermediate section to atleast one handling cable or rope or to a pair of handling cables orropes each one of which is wound up on an associated operating winchlocated on the ship whereby the ramp may be raised through a poweredaction or lowered through gravity. The innermost section is partiallysuspended from each handling rope because the latter is kept taut with adetermined constant tension corresponding for instance to the totalweight of the loading ramp and each rope may be automatically wound upor paid out according to the variation in the load. At least one winchand possibly both powered winches for extending the intermediate sectionare mounted on one or both of the side frame members, respectively, ofthe innermost section and the rope of each winch is successively reevedonto a first guide sheave or pulley carried by the free end of saidextension boom and onto a second guide pulley or sheave carried by theintermediate section to be made fast at a stationary point of said boom.The outermost section, forming a supporting pad or flap member to enablethe ramp to bear onto the quay, is pivotally connected substantially atits centre of gravity to said intermediate section so as to be always atpoise, i.e. in a state of indifferent equilibrium or like balancedcondition about its substantially horizontal pivot axis.

This known appliance exhibits various inconveniences since on the onehand it requires a relatively complex special mechanism to achieve atemporary engagement or like bearing connection between each boom end inextension of one side frame member of the innermost section with acorresponding sidewise projecting supporting pad of the intermediatesection and on the other hand it requires the provision of at leaststate of indifferent equilibrium, i.e. likely to take any relativeangular position about its swivel axis, there may be a possibility thatthis section, when being lowered onto the quay, is not in the properrelative position, i.e. substantially in parallel relation to the quaysurface so that there may be a wrong bearing in particular in view ofsome buttressing or abutting effect so that a manual action has to betaken to overcome or obviate such a difficulty.

One main object of the invention is therefore to remove theaforementioned drawbacks inherent in the prior known state of the art byproviding a device of a simpler hence more economical constructionperforming a more effective and reliable operation. For this purpose theinvention is starting from the known kind of movable device forming afoldable access ramp for interconnecting a vehicle and an outsideplatform, which is swingable in parallel relation to a vertical plane sothat it may be raised upwards to an inoperative position in a stowed orlashed condition on said vehicle and lowered downwards to anoperativeworking position for resting partially on said platform, saidramp comprising at least two successive sections pivotallyinterconnected endwise in the longitudinal direction thereof, the firstone of which forms the innermost or inboard section which is pivotallyconnected to said vehicle and secured with at least one point to atleast one handling cable always kept taut and wound up onto at least onewinch located on said vehicle whereas the other or second section may befolded back downwards against and along the first one and is fastened toat least one handling cable for extending said other section to aposition which is at least approximatively in aligned registeringrelation to said innermost section in the lowered working condition ofthe ramp. To solve the technical problem set, the invention thereforeproposes a device of the aforesaid kind which is characterized in thateach handling cable for extending said other section is connected tomeans for tensioning and for automatically taking up any possible slackof said cable through the action of potential energy, which means arelocated on said vehicle and include self-acting means for automaticallyand unidirectionally stopping the cable and holding it against motion,said means being adapted to provide a stationary fastening point forcausing through locking of the effective useful length of said cable, atractive reaction force to arise for extending said other section duringthe downward motion of said innermost section which is always suspendedfrom each aforesaid handling cable.

Such an arrangement offers the advantage to enable the second rampsection to be extended without the use of any powered winch for thispurpose but by exclusively making use of the potential energy stored inthe innermost ramp section in its raised position whereby said innermostsection tends byitself to rock or tilt naturally downwards throughgravity under the action of its own weight while causing at the sametime the adjacent ramp section to be extended accordingly. At thebeginning or during the initial period of downward motion of theinnermost section from its substantially vertically or upright raisedand stowed position, the component of the total ramp weight which islikely to act upon each handling cable for extending said adjacentportion is inadequate for exerting any significant rotary effectthereon, so that according to another characterizing feature of theinvention, said automatic means for 4 stopping and unidirectionallyholding against motion each handling cable for extending said adjacentsection are arranged so as to be operative only from some determinedangle of slope for instance of about 20 of the innermost section withrespect to the vertical direction during the starting period of downwardmotion thereof.

According to a further characterizing feature of the invention, as saidinnermost ramp section is suspended from the end of each aforementionedhandling cable, there are provided selectively adjustable load transfermeans for varying at will the bearing reaction of the ramp onto saidplatform in the extended working configuration of the ramp therebytransferring at least one selectively variable part of the weight andinstant load of said second ramp section either onto said innermost rampsection or onto an independent auxiliary supporting system mounted onsaid vehicle. Such an arrangement offers the advantage to possiblyachieve an automatic control of the bearing pressure force of the ramponto said platform in accordance with the true load carried by saidsecond ramp section.

According to still another characterizing feature of the invention, themeans for tensioning and automati cally taking up the slack of eachcable controlling the extension of said second ramp section consist of amovable counterweight and for this purpose each handling cable forcontrolling the extension of said second ramp section is reeved on atleast one preferably elevated or overhead loose guide pulley 0r idlesheave mounted on said vehicle to terminate into said counterweightwhereas said automatic means for stopping and unidirectionally holdingagainst motion consist of a stationary stop means provided on saidvehicle for limiting the upward motion or stroke of said counterweight.

According to a further characterizing feature of the invention, eachaforesaid counterweight has a selectively adjustable weight to provideone aforesaid load transfer means.

According to an alternative embodiment, each aforesaid handling cablefor controlling the extension of said second ramp section is connectedto a stationary fastening point provided on said vehicle through themedium of an adjusting member having a selectively variable length, suchas a turn buckle or like tension shackle, rope tightener or stretcherforming an aforesaid tensioning and load transfer means.

According to a modification, each aforesaid handling cable forcontrolling the extension of said second ramp section is connected to apressure fluid-operated lineardisplacement actuator for example of theram type having a selectively adjustable force to form an aforesaidtensioning and load transfer means.

Accordingto still another alternative embodiment, said automatictensioning and slack taking-up means consist of at least one resilientlydeformable spring-like member and for this purpose each aforesaidhandling cable for controlling the extension of said second ramp sectionis connected to a stationary fastening point provided on said vehiclethrough the medium of this spring, whereas said automatic means forstopping and unidirectionally holding against motion consist of astationary stop means for limiting the strain or deformation of saidspring under maximum stress.

According to a further alternative embodiment, said automatic tensioningand slack taking-up means consist of a possibly self-acting winding-upappliance to which each aforesaid handling cable for controlling theextension of said second ramp section is connected whereas saidautomatic means for stopping and unidirectionally holding against motionconsist either of the stationary fastening point of the end of saidcable on said appliance or of a locking or braking member of saidappliance for braking said cable at the end of its useful paying-outmotion.

According to still a further modification of the invention, eachaforesaid handling cable for controlling the extension of said secondramp section is connected to a power winch as known per se and thewinding-up device consists of said winch which is preferably providedwith means for keeping the cable tension constant and is located on saidvehicle to form an aforesaid load transfer means.

Finally according to still another alternative embodiment, said loadtransfer means consist of at least one counterweight or likecounterbalancing or weighting body and preferably of a body with anadjustable weight fitted on one lever arm fast with said second rampsection so as to bias or urge same upwards i.e. towards its extendedposition.

When the ramp comprises, as known per se, a third or outermost sectionforming a supporting pad for bearing engagement with said outsideplatform and which is pivotally connected preferably with anintermediate point thereof to the corresponding outer end of said secondsection forming an intermediate section, there are provided self-actingor operated means for raising said outermost section. For this purposeand according to one embodiment of the invention, each handling cablefor controlling the extension of said intermediate section is reeved asknown per se on at least one, associated main loose guide pulley orsheave carried by said intermediate section and this cable is securedwith its aforesaid outer end at a point located outwards beyond thepivotal connection of said outermost section with said intermediatesection. Such an arrangement offers the advantage to enable saidoutermost section to be automatically raised so as to assume a properflat-laid position when engaging the quay thereby preventing anypossibility of buttressing or abutting against some projection of thequay.

According to an alternative embodiment, an operated means forcontrolling the raising of said outermost element may consist of atleast one preferably lineardisplacement, pressure fluid operated forinstance ramp-like actuator mounted between the intermediate andoutermost ramp sections and remote-controlled either automatically or byan operator from a remotecontrol station or desk.

Moreover, in the device according to the invention, the ramp, in itslowered and extended working condition, remains at least partiallysuspended from its handling cables or ropes reeved on the associatedkingposts, respectively, of the ship and made fast adjacent to the outerend of the inboard ramp section (i.e. that section which is pivoted tothe ship) so a to relieve the quay from the load sustained by decreasingthe bearing pressure of the free end of the ramp thereon by transferringor carrying over at least one part of the total ramp weight and of itspossible instant load to the ship. The bearing pressure exerted onto thequay by the outermost ramp section may also or in addition be decreasedby applying a suitable adequate tension to the handling cables or ropesfor controlling the extension of said intermediate section, so thattheir reeved portions between pulley or tackle blocks, interconnectingthe innermost ramp section and the adjacent outer or intermediate rampsection pivotally connected thereto thereby exerts a relative liftingforce on the combination of said intermediate ramp section and outermostramp section for thereby transferring at least one part of the weight ofsuch an assembly and of the instant load possibly carried thereby tosaid innermost ramp section while unidirectionally blocking the pivotaldirection between both innermost and intermediate ramp sections in therelative swinging direction for holding same together (and this at leastto some extent).

Such a load transfer to said handling cables required at least in partowing to the fact that the ramp forms a beam consisting of severalpivotally interconnected sections results in applying correspondingtractive forces to the tops of said king-posts which are extendingupwards to a relatively large height above the level of the horizontalcentre line passing through the centre of gravity of the ship so thatsuch tractive forces are applied to the ship with a rather significantlever arm generating a corresponding tilting moment tending to cause theship to list or to be tilted to the side where the ramp is locatedthereby heeling over.

To remove or obviate such a drawback to a large extent, i.e. to preventthe ship from listing or heeling over during the use of the ramp, it isknown in particular from the US. Pat. No. 3,687,308 to provide on atleast one side frame member of the innermost ramp section pivotallyconnected to the ship, a pressure-operated extensible and retractableactuator with a substantially linear displacement in translatory motion,in particular of the ram-type formingg a cylinder and piston assemblythe line of action of which is spaced from the geometrical pivot axis ofthe pivotal connection between both inner and outer or intermediateadjacent ramp sections, said actuator being adapted to removably bearagainst an abutment member rigidly secured to the corresponding side ofsaid adjacent outer section in the extended and lowered workingconfiguration of said ramp for locking said pivotal connection in thedirection of rotation of increasing extension in a selectively variablerelative angular position through the adjustable active extension lengthof said actuator whereas selectively variable connecting means betweensaid side frame member and said corresponding side, respectively, ofboth ramp sections involved enable to lock said pivotal connection inthe direction of rotation of ramp folding in the same relative angularposition. In this known prior art arrangement, said actuator bears uponthe adjacent outer ramp section through the medium of an arm pivotallyconnected to said inner ramp section and slidably engageable with theadjacent outer ramp section and said selectively variable connectingmeans consist of handling cables or ropes for controlling the extensionof said outer ramp section and one reeved portion of which interconnectsboth pivotally interconnected ramp sections, these cables being operatedby at least one winch mounted on the inner ramp section and adapted toexert a selectively adjustable fixed tension on said cables controllingthe extension of said outer ramp section. Such a combined system enablesto achieve a buttressing effect locking or holding against motion thepivotal connection between both aforesaid ramp sections in both oppositedirections of rotation thereby preventing any variation in the relativeangular position of both ramp sections involved (with attendant upwardor downward motion of the absolute position of the pivotal connection inspace), so that the ramp behaves bodily as a bridge-like stiff or rigidcontinuous beam which is suported on the quay and by the pivotalconnections with the ship at a location very close to the centre line ofgravity of the ship thereby reducing by a corresponding amount thelength of the lever arm generating the aforementioned tilting or tippingmoment hence the possible resulting list of the ship.

The aforesaid known construction exhibits several inconveniences. On theone hand, the pushing buttressing actuator and pivoted arm assemblyengaging a sidewise projecting abutment directly intergral with therunway forming the intermediate or outer ramp section which isdevoid ofside frame members, is of a rather complicated construction. On theother hand the use of a cable or rope system in combination with thebuttressing actuator exhibits the disadvantage of separating thebuttressing functions in both opposite directions of rotations,respectively, of the pivotal connection, thereby also complicating theconstruction to a significant extent. Moreover, the locking effectachieved by the cables controlling the relative extension of theintermediate or outer section by means of their associated individualwinch does not allow to achieve an absolutely positive locking effect,i.e. resulting in an adequate stiffness of the ramp in the relativelifting direction of the pivotal connection, thereby decreasing theeffectivenes of the desired locking action by a corresponding amount.Said known system is accordingly rather expensive, of a rather difficulthandling in view of the difficult mutual adaptation of both separatelocking functions in opposite directions, respectively, and of a ratherunreliable effectiveness and operation.

There are in addition known ramps consisting of three pivotallyinterconnected sections the innermost section of which is pivoted to theship while being suspended from a pair of cables or ropes made fast withone end to the ship and with the opposite end to the oppositelongitudinal edges, respectively, of said innermost ramp sectionadjacent to theouter end thereof.

On either longitudinal side of the innermost section is pivoted thebottom or back end of the cylinder of a linear-displacement typepressure fluid operated actuator extending substantially in parallelrelation to the relative vertical longitudinal plane of said side framemember and the piston rod of which s pivotally connected with its end tothe adjacent inner end of the adjacent intermediate ramp section.

In Applicants co-pending U.S. Pat. Application Ser. No. 380,469 filed onJuly 18, 1973 and not yet publicly disclosed is proposed a foldable rampwhich may be raised and lowered and consists of three pivotallyinterconnected sections the innermost section of which is pivoted to theship and suspended from handling cables or ropes kept taut or stretchedwith an adjustable constant tension (and wound up on respective winchesprovided on the ship) adjacent to its outer ends of its opposite sideframe members forming a kind of guardrailing. The central orintermediate ramp section also comprises side frame members forming akind of guard-railing on its opposite sides and a lineardisplacementbuttressing actuator is mounted on either longitudinal side of the rampon the adjacent ends of the side frame members of the inner and centralramp sections, respectively, above the pivotal connection therebetweenand in the relative longitudinal vertical plane of the side framemembers in the lowered working position of the ramp, therebyinterconnecting these ends so as to exert a buttressing effect onto theramp. The cylinder of each actuator is mounted on the innermost rampsection so that each actuator exerts through its piston rod a thrust orpushing force onto the adjacent intermediate ramp section, whereby thepivotal connection between both of these ramp sections may be liftedupwards or raised in space so as to form an upward projecting angletherebetween.

One object of the invention is also to remove said drawbacks byproviding a double buttressing arrangement of a simpler hence lessexpensive construction and combining into one single and same assemblythe functions of locking the pivotal connection between both rampsections in either of the opposite directions of relative rotationthereof, respectively. For this purpose the device according to theinvention is characterized in that on the one hand said actuator ispivotally connected with its casing or body portion onto the side framemember of said innermost ramp section and extends substantially inparallel relation to the relative longitudinal vertical plane of saidside frame member and higher than the geometrical pivot axis betweenboth innermost and central ramp sections in the working position of theramp whereas said central ramp section also comprises a pair of sideframe members on its opposite longitudinal sides, respectively and onthe other hand the movable thrust or pushing head of said actuator isfreely engageable directly with at least one substantially concavethrust or buffer or like pad means forming said abutment member andsecured onto the adjacent end of a corresponding side frame member ofsaid outer ramp section, operated or boosted locking means beingprovided on said corresponding side frame member of said outer rampsection to rigidly connect said actuator head with said thrust or buffermember, these means forming said selectively variable connecting means.

In addition to the aforesaid advantages aimed at by the objects of thepresent invention, such an arrangement is also advantageous in view ofits rather more reduced size as compared with the known system. Moreoverthebuttressing actuator serves itself as a bracing or like tie-memberinvariably connecting together both interconnected ramp sections in thelocking position of the actuator thereby positively and effectivelypreventing any relative folding or rotary motion about the pivotalconnection between both ramp sections involved.

According to another characterizing feature of the invention, themovable thrust head of said actuator comprises at least one sidewiseprojecting portion such as for instance a transverse projecting stud-pinadapted to bearingly engage said buffer member or pad or like abutmentmeans which is preferably a substantially square-shaped bracket and saidlocking means comprise at least one movable retaining member actuated inparticular by an associated power-operated actuator and mounted on saidadjacent outer ramp section, said retaining member being adapted toengage said studpin or like trunnion member to keep it in abuttingengagement with said thrust or buffer pad.

According to still another characterizing feature of the invention, eachaforesaid retaining member is constantly biased or urged automaticallytowards its operative locking position either by a resilient spring-likebiasing or return means or by gravity so that its associatedpower-operated actuator serves for unlocking purposes only.

This retaining member thus provides a temporary rigid working assemblysecured against any separation, disengagement or like disconnection andagainst any slipping or sliding motion through mutual displacement,preferably by a shape-conditioned stop means or fit or the like therebyachieving a closed assembly.

Owing to its technical unobvious effects and advantageous resultsobtained the device according to the present invention brings about asubstantial progress or advance or significant improvement overpreviously known devices of the same kind.

The invention will be better understood and further objects,characterizing features, details and advantages thereof will appear asthe following explanatory description proceeds with reference to thediagrammatic accompanying drawings given by way of non limiting examplesonly illustrating various presently preferred specific forms ofembodiment of the invention and wherein:

FIG. 1 shows a perspective view of the ramp of the invention accordingto a first embodiment thereof, with a second ramp section provided withcantilever booms or outriggers or like projecting arms, the ramp beingmounted astern i.e. at the rear portion of a ship moored longitudinallyalong a quay berth and shown in its lowered extended workingconfiguration wherein its longitudinal direction makes an acute anglewith the general backwards pointing longitudinal direction of the ship;

FIG. 2 is a fragmentary top view of the arrangement shown in FIG. 1;

FIG. 3 is a fragmentary side view on a larger scale showing the ramp ina raised and folded stowing position, in an intermediate handlingposition in a partially lowered and extended state and in two loweredand extended working positions, respectively, in both cases where theaccess area of the ship is located higher or lower than the quaysurface, respectively;

FIG. 4 is a partial side view of the upper right-hand portion of FIG. 3showing the use of a counterweight for each handling cable controllingthe extension of said second ramp section;

FIG. 5 is a view similar to FIG. 4, showing an alternative embodimentillustrating the use of a hydraulic actuator for each handling cablecontrolling the relative extension of said second ramp section;

FIG. 6 is a view similar to FIGS. 4 or-5, showing another modificationillustrating the use of a spring for each handling cable controllingsaid relative extension of the second ramp section;

FIG. 7 is a view similar to FIGS. 4 to 6, showing still a furtheralternative embodiment illustrating the use of a constant-tension winchfor each handling cable controlling the relative extension of saidsecond ramp secvention wherein said cantilever booms or projectingoutriggers are carried by the innermost ramp section instead of beingcarried by the intermediate ramp section;

FIG. 10 is a fragmentary side view of the preceding device shown in itsraised and folded stowing position;

FIG. 11 is a view similar to the preceding one but corresponding to theconfiguration shown in FIG. 9 when assuming the level of the access areaof the ship to be approximately the same as or slightly higher than thatof the quay;

FIG. 12 is a fragmentary side view on a larger scale in the encircleddetail XII of FIG. 3;

FIG. 13 is a view similar to FIG. 11 but wherein the access area of theship is assumed to be located higher than the quay surface;

FIG. 14 is an enlarged fragmentary side view of the encircled detail XIVin FIG. 13;

FIG. 15 is a view similar to FIG. 11 or 13 but wherein the level of theaccess area of the ship is assumed to be located below the quay surfacelevel;

FIG. 16 is an enlarged fragmentary side view of the encircled detail XVIin FIG. 15;

FIG. 17 is a fragmentary side view on a larger scale, similar to FIGS.10, ll, 13 and 15 and showing the ramp in different successive end andintermediate positions, respectively, to show the various steps of itsoperation in both cases where the access area of the ship is locatedlower and higher, respectively, than the quay surface;

FIG. 18 is a fragmentary outside lateral view, with parts broken away,of the ramp portion located adjacent to the pivotal connection betweenthe innermost and central or intermediate ramp sections in a relativeconfiguration partially folded with an upward projecting angle, saidportion being provided with a device according to the invention, placedin its retracted inoperative position, i.e. without producing anybuttressing effect;

FIG. 19 is a fragmentary side view on a larger scale of a still morereduced ramp portion about its pivotal connection in a relative loweredand extended working position with the innermost and intermediate rampsections substantially aligned in mutually registering relationship inextension of each other, said buttressing appliance being in itsoperative extended position; and

FIG. 20 is a fragmentary top view of the adjacent end portions of bothcorresponding side frame members of both ramp sections involved,respectively, shown in the preceding Figure.

According to the exemplary form of embodiment shown in FIGS. 1 to 8, aship, generally denoted by the reference numeral 1 and the stem or rearend portion of which only is shown, is moored adjacent a quay 2 forinstance alongside thereof, so that the longitudinal direction 3 of theship is substantially parallel or coextensive with the direction of thequay edge. The rear portion of the ship is fitted with a movable accessramp 4 consisting of three successive innermost or foremost, central orintermediate and rearmost or outermost sections 40, 4b and 4c,respectively, pivotally connected to each other in the longitudinaldirection in substantially aligned mutually registering relationship inthe lowered extended working position by pivot hinges or the like 5, 5',respectively. The outermost section 40 is desirably in the shape of abearing pad or like engaging plate serving to support the ramp onto thequay 2, so that this section automatically conforms to the quay surfaceirrespective of the relative slope of the intermediate section 4b. Inorder to facilitate the passage of vehicles on the ramp, the outermostsection 40 is as known per se wider on at least one side and at leasttowards its free end than the adjacent intermediate section 4b. Theinnermost or inboard section 4a is made desirably wider at least towardsone side as known per se at its forward or inner end through which it ispivoted at 6 to the ship 1.

At least the innermost section 4a is provided on either side thereofwith two side frame members 7. The innermost section 4a is securedpreferably at its outer ,end or adjacent to its pivotal connection withthe intermediate section 4b to at least one handling cable or rope woundup on an associated power-operated handling winch located on the ship.There are preferably provided at least two handling cables 8, 8 madefast at 9, 9', respectively, onto the side frame members 7 of the rampsection 4a and winding up on two corresponding handling winches 10, 10',respectively, desirably located at an overhead or elevated level, forinstance on the upper deck 11 of the ship. Each handling cable 8, 8,extending from its associated power-operated winch l0, 10' passes atfirst on at least one preferably elevated auxiliary guide pulley orsheave mounted for instance on a deck erection or like superstructuresuch as a suitable king-post or mast 13, 13 (at the bottom portions ofwhich the winches 10, 10 are located) and then on at least one mainguide-pulley 9, 9' mounted on the side frame members 7 of the rampsection 411. In order to reduce the tractive force to be exerted on thehandling cables 8, 8, it is advantageous that each handling cable 8, 8forms a suitable reeved portion or the like interconnecting the rampsection 4a with the corresponding king-post l3, 13 while thus passingsuccessively on several auxiliary guide-pulleys l2, 12 mounted in a samepulley or tackle block carried by the corresponding king-post 13, 13 andthen on several main guide-pulleys-9, 9' also fitted together in a sametackle block secured to the corresponding side frame member 7, 7'. Eachcable 8, 8 thus exhibits multiple runs extending between the ship andthe ramp. To balance the tensions in the various runs of the cables 8,8, one single cable only is used which, extending from the winch 10 andafter having passed on the pulley-blocks l2 and 9 is reeved at 8"successively onto the guidepulleys 9a, 9a located beneath the rampsection 40 at the outlet of pulley-block 9 and the inlet of pulleyblock9', respectively, for passing then on the latter and afterwards on thetackle-block 12 to be finally taken up by the other winch 10.

As known per se, the intermediate section 4b is foldable downwardsagainst the innermost section 4a along the latter and secured at atleast one point and preferably at two points 19, 19 located for examplesidewise of each side on the opposite longitudinal edges, respectively,to at least one and preferably two handling cables l5, l5 controllingthe relative extension of said intermediate section and passing each oneon at least one loose guide sheave and for instance two looseguide-sheaves 16, 16 which are preferably at an elevated position andcarried for instance by a king-post or the like l3, 13, respectively, tobe made fast through the medium of a turn-buckle, rope stretcher orstiffener or like cable tensioning or tightening device 17, 17 to astationary point 18, 18 fast for instance with the associated king-post13, 13'.

As known per se the intermediate section 4b extends beyond its pivotalconnection 5 with the innermost section 40 with at least onelongitudinal projecting armlike boom or integral outrigger carryingtowards its free end at least one auxiliary guide-sheave for eachhandling cable 15, 15 controlling the extension of said intermediatesection. For this purpose there are desirably provided two suchcantilever arm-like booms or projecting outriggers 23, 23 consisting ofoutwards offset extensions of the corresponding longitudinal edges ofthe intermediate section 4b beyond the pivotal connection 5 forming theouter end of the vehicle runway sup ported by the side frame members 7of the innermost section 4a, these booms being preferably arranged so asto be located higher than the innermost section 4a in the extendedposition of the ramp and to embrace the latter. Each projecting boom 23,23' carries at least one auxiliary guide-pulley 19, 19' for the handlingcable 15,15 controlling the extension of said intermediate section,which thus is reeved successively over this pulley 19, 19' and then on amain loose associated guide-pulley 14, 14' carried by the innermostsecton 4a respectively at the corresponding auxiliary sheave 19, 19' tobe made fast at a stationary point 14a, 14b on the associated side framemember of the innermost section 4a. There are desirably provided, oneach boom 23, 23', several auxiliary loose guide-pulleys l9, 19' mountedin a same tackle-block and, on the innermost section 40 on either sidethereof, several loose main guide-pulleys 14, 14 also mounted in a sametackleblock so as to form a force-reducing reeving between each boom 23,23 and the innermost section.

At least one (hydraulic or pneumatic) pressure fluid operated actuator,preferably of the lineardisplacement type consisting of a cylinder andpiston assembly mounted between the intermediate ramp section 412 andthe innermost ramp section 40 and pivotally connected with its cylinderbottom or back end to the end of the section 4b and with its piston rodto the end portion forming the heel part of the section 40 located underthe section 4b (see FIG. 3). This actuator is desirably provided andremote-controlled for raising the innermost section 4c so that thelatter rests entirely throughout its seating surface in a flat-laidcondition onto the quay 2, so as to properly connect the runway surfaceof the intermediate section 4b to the quay surface and to distribute theload uniformly on the latter to avoid any buttressing, punching or likeeffect. FIG. 2 shows that it is advantageous to provide two suchactuators 26 preferably arranged in symmetrical relation to thelongitudinal vertical center plane of the ramp towards the side edges,respectively, of the innermost ramp section 4c. Independent segmentedflap elements 27 pivoted to the transverse end edge of the section 40 injuxtaposed relationship across the latter serve to engage the quay 2 tofacilitate through their tapering wedge-shaped cross-sectional contourthe access to the section 40. Also, a set of similar flap elements 28are likewise pivoted to the inner transverse end edge of the rampsection 4a'to facilitate the access to the tweendeck 29 of the shipwhile spanning the cargo port 30 in the side thereof.

The tractive reaction force at the fastening point of each handlingcable 15, 15' controlling the extension of the intermediate section, onits associated derrick or 13 king-post 13, 13' may be produced invarious ways. Thus in FIGS. 1 and 3, this reaction force is merelyproduced by the stationary fastening point l8, 18 of each cable at thetop of the associated king or derrick post. In the alternativeembodiment according to FIG. 4, each cable 15, 15', after having beenreeved over a first guide-pulley 16 located at the free end of the jibportion of the associated king-post or derrick mast 13, 13' passes on asecond guide-pulley 16a located at the opposite end of this jib portionto extend downwards again along the king-post and to terminate into amovable counterweight or the like 31 mounted for instance on rollers 32for riding on or within a corresponding forced-guide track 33 slopingdownwards from top to bottom and away from the ramp in the downwarddirection. This guide-track 33 is provided at its upper end with astationary stop means 34 for limiting the upward stroke of theassociated counterweight 31. The position of the counterweight obviouslyvaries with the relative position of the ramp during operation thereof,the engagement of the counterweight 31 with the stop means 34automatically causing the relative raising and extension of theintermediate ramp section 4b.

In the alternative embodiment according to FIG. 5, each cable 15, 15',after passing over the associated guide-pulley 16a is reeved on aguide-pulley 35 carried by the piston rod of a linear-displacementpressure fluid operated, for example, hydraulic actuator 36 mounted onthe associated king-post 13, 13', the thus returning run of each cable15, 15' being made fast at a stationary point 37 of the correspondingderrick mast or king-post. Each actuator 36 thus allows to vary at willand preferably at the same time or synchronously the tension in theassociated cable 15, 15' in particular through selective adjustment ofthe control fluid pressure fed into the cylinder of actuator 36.

In the alternative embodiment shown in FIG. 6, the pressure fluidoperated actuator 36 has been replaced by a spring-operated actuator orthe like 38 secured to the corresponding king-post 13, 13' andcomprising for instance a cylinder containing at least one for instancehelical compression spring with one end of which cooperates a slidingpiston coaxially integral with a rod carrying at its free outer end thepulley 35. The helical spring could possibly be replaced by acompressible preferably gaseous fluid such s nitrogen.

In the embodiment of FIG. 7, each cable 15, 15', after passing on theguide-pulley 16, 16, is wound up on a power-operated winch 39 preferablyapplying a constant tension to the cable and mounted on the associatedking-post 13, 13, said winch being driven for example hydraulically orelectrically.

The actuators 36 in the embodiment of FIG. or the winches 39 in theembodiment of FIG. 7 allow to selectively vary the tension in the cables15, in the extended and lowered working configuration of the ramp 4,thereby tending to lift the intermediate ramp section 4b upwards to thusrelease selectively the bearing pressure exerted on the quay 2 by theoutermost ramp section 4c. Another means enabling to produce the samerelief effect consists according to the embodiment of FIG. 8 to provideon each projecting boom 23, 23' of the intermediate ramp section 4b acounterweight or the like 40 having for instance a selectively variableweight and desirably located endwise of the associated projecting boom23, 23'. Each counterweight 40 thus applies a tilting moment to thesection 4b about its pivot axis 5 in the upward direction or directionof raising of said section. Instead of a counterweight it is alsopossible to correspondingly weight the structure of the booms 23, 23' byincreasing their mass.

Automatic control means are desirably provided to keep the innermostsection 4a away or spaced from the quay in the lowered workingconfiguration of the ramp in order that it never directly engages thequay and each operating winch 10, 10' is phase-locked in followuprelationship to these control means which consist for instance of atleast one sensor or like detector 21 (see FIGS. 2, 3 and 8) secured forexample to the intermediate section 4b in particular below same andtowards its inner end and adapted to bear upon the surface of the quay2, preferably adjacent to the edge of the quay to'detect any variationin relative position in height or in the level difference between theship I and the quay as caused in particular by an upward motion of theship. Such a sensor 21 may consist for example of an electric limitswitch with normally open contacts adapted to'control the simultaneousor synchronized operation of the respective motors or prime movers ofthe handling winches 10, 10' by acting for instance either upon anelectromagnetic valve in the case of pressure-fluid operated motors suchas hydraulic or pneumatic motors or upon an electric switch relay in thecase of electric motors.

The system is desirably fitted with automatic control means foradjusting the relative angular position of the innermost andintermediate ramp sections 4a and 4b,

a respectively, to keep same substantially aligned or inclinedwith anoptimum slope in the lowered extended working configuration of the ramp,each aforesaid handling winch 10, 10' being then phase-locked infollowup relationship to such control means. These control means consistfor example of at least one sensor or like detector 22 mounted on one ofthe two adjacent ramp sections 4a, 4b, preferably in the vicinity of itspivotal connection 5 with the other section and adapted to engage saidother section so as to measure the angle formed therebetween inparticular during the raising motion of the ship. In the example shown,this detector 22 is mounted on the protruding boom 23 of theintermediate ramp section 4b between the latter and the side framemember 7 of the innermost ramp section 4a. This detector 22 may as wellas the sensor 21 consist advantageously of an electric limit switch orof a position pick-up or detecting means with an equivalent action.

In the embodiment of FIGS. 1 through 8, each aforesaid protruding boom23, 23' is in extension of the corresponding side edge of theintermediate section 4b. It is apparent however that generally eachprojecting boom may be in extension of any one of the two innermost andintermediate ramp sections 4a, 4b, respectively, while extending beyondthe common pivotal connection between the adjacent ends thereof towardsthe other section which then carries at least one main guide-pulley ortackle-block for the handling cable 15, 15' controlling the extension ofthe intermediale section whereas the free end of the corresponding boomthen carries at least one auxiliary guide-pulley or tackle-block forthis cable.

FIGS. 9 through 17 show another embodiment of the invention wherein therelative arrangement of said booms and sheaves or pulley-blocks has beenreversed with respect to that of the first embodiment shown in FIGS. 1to 8. In this alternative embodiment, it is the innermost ramp section40 which extends beyond its pivotal connection 5 with the intermediatesection 4b with at least one integral projecting longitudinal armlikeboom or outrigger and preferably with two such booms 7a, 7bsubstantially co-extensive in parallel relationship with the generallongitudinal direction of the ramp in extension of the side framemembers 7, on either side of the intermediate section 4b while beingdesirably transversely offset outwards so as to be spaced sidewise fromthe intermediate section 4b and preferably somewhat elevated or higherwith respect thereto. Each projecting boom 7a, 7b then carries the oreach main guide-pulley or tackle-block 19, 19' for the han dling cable15, controlling the relative extension of the intermediate section,whereas the intermediate section 4b carries at an intermediate pointthereof at least one auxiliary guide-pulley or tackle-block 14, 14' foreach handling cable 15, 15' controlling the extension of saidintermediate .section and leading from each main guide-pulley ortackle-block 19, 19'. Each handling cable 8, 8' for the ramp is thenmade fast for instance with a tackle-block at a point 9, 9' of theinnermost section 4a towards the pivotal connection 5 or outer end ofsame. On each king-post or derrick mast 13, 13', the free downwardextending run of each cable 15, 15 terminates in a counterweight or thelike 31, 31'. Each king-post 13, 13 comprises a stationary stop means34, 34' limiting the upward vertical stroke of the associatedcounterweight 31, 31.

Each handling cable 15, 15' controlling the relative extension of theintermediate ramp section is desirably made fast with the end of its runleading from the corre sponding reeving portion 14, 14' thereof andafter havin g passed over an additional guide-pulley 25, 25 (FIGS. 10,11, l3, 15) to the outermost section 4c at a point 20, located outwardsbeyond the pivotal connection 5' of this outermost section with theintermediate section 4b. The cables 15, 15 also serve to automaticallyraise or lift the outermost section 4c so that the latter rests entirelythroughout its seating surface on the quay 2 thereby properly connectingthe runway surface of the intermediate section 4b to the quay surfaceand distributing the load uniformly on the latter to avoid any punchingor like buttressing effect. This arrangement is also applicable to theembodiment of FIGS. 1 through 8 instead of the actuators 26 and it isadvantageous that each guide-pulley 25, for each handling cable 15, 15'controlling the relative extension of the intermediate section belocated preferably substantially at the pivotal connection 5 between theinnermost section 4a and the intermediate section 4bfor instance incoaxial relationship therewith to return or guide backwards theassociated cable 15, 15' leading from the guide-pulley or tackle-block14, 14 to the fastening point 20, 20' provided on the outermost section40.

Pushing or thrust means such as one or several lineardisplacement typepressure-fluid operated for instance hydraulic or pneumatic actuatorswith a cylinder and piston assembly 24 mounted on the ship 1 are adaptedto bear freely in abutting relationship against the innermost rampsection 4a in the fully raised position thereof (FIG. 3) to initiate itsdownward tilting or swinging motion through gravity and possibly tobrake or slow down same at the end of its raising motion at which it isengageable with stationary stop or rest means 41 forming wooden orrubber buffers or like pads provided on the ship. Alternatively thesethrust actuators 24 could themselves form such stop or abutment means.Each actuator 24 instead of being mounted on the ship 1 could as well bemounted on the innermost ramp section 4a so as to be freely engageablewith a stationary portion of the ships structure at the start of thedownward tilting or swinging motion of the ramp or at the end of theraising motion thereof.

The innermost section 4a is desirably enlarged or widened at 4 towardsits inner end and preferably at least towards the obtuse angle definedbetween its own longitudinal direction and the longitudinal direction ofthe ship in the case of a ramp arranged towards one end for example aftof the ship with a view to facilitate access therto.

A lashing or locking appliance 42 is desirably provided on the ship forlocking or holding the ramp 4 against motion in the stowed noperativeposition, i.e. when it is folded back and swung up (see FIGS. 3 to 7).Each locking or lashing device 42 is adapted to preferably engage theintermediate ramp section 4b folded downwards against the innermostsection 4a which has come in abutment with the buffers 41 after havingbeen run or extended through the latter, Each locking device 42 may beoperated either manually or automatically for instance may hydraulicactuators and consist in particular of a latch, lockbolt or like hookmember adapted to engage a bolt-clasp or equivalent catch or keepermeans integral with the intermediate section 4b while preferablyexerting a tractive force urging said ramp to bear against its abutmentpads or buffers 41. Instead of being placed on the ship 1, each lockingdevice 42 could also be provided on the ramp 4 to be engageable with acomplementary or mating stationary catch element integral with the shipsstructure.

Automatic control means, not shown, are advantageously provided toselectively vary the bearing reaction of the ramp 4 on the platform orquay 2, each aforesaid load transfer means, such as in particular thehydraulic actuators 36 or the winches 39 applying a constant tension tothe associated cables, being then phase-locked in follow-up relationshipto said control means. These control means consist for instance for asensor or like detector forming a pressure pick-up device mounted on theramp towards its outer end for bearing upon the quay 2 in the workingposition so as to measure the bearing reaction of said quay.

As shown in particular in FIGS. 10 to 16, each sensor element 21 is heresecured to the innermost section 4a in particular underneath the latterand towards its outer end whereas the detector 22 is mounted on theintermediate ramp section 4b between the latter and the projecting boom7a of the innermost ramp section 4a.

The operation of the ramp 4 is then the following with reference atfirst to FIG. 3 showing the first embodiment when assuming the rampinitially in the position C wherein it is folded back and entirelyraised to an upstanding position. In thisposition, the ramp is heldagainst motion in abutment against the buffers 41 by the lockingarrangement 42, the ramp sections 4b and 40 being folded back againstthe section 4a. To lower the ramp into the extended working position,the locking device 42 is at first unlocked in order to disengage orrelease the ramp 4 and the winches 10, 10 which are desirably providedwith means for automati-

1. A movable device forming a foldable access ramp to interconnect avehicle with an outside platform, said ramp being adapted to swing inparallel relation to a vertical plane so as to be raised intoinoperative stowed position on said vehicle and lowered into operativeworking position to rest at least partially on said platform, said rampcomprising at least two successive ramp sections pivotallyinterconnected endwise in the longitudinal direction and the first oneof which forming an innermost section is pivotally connected to saidvehicle and attached with at least one point of said ramp section to atleast one constantly tensioned handling cable winding up on at least onewinch located on said vehicle whereas the other or second ramp sectionmay be folded back and downwards against and along said innermost rampsection and is attached to at least one handling cable controlling itsoutward extension for raising said other ramp section into the extendedposition in at least approximatively aligned registering relationshipwith said innermost ramp section in the lowered working position,wherein the improvement consists in that each handling cable forcontrolling the outward extension of said second ramp section isconnected to means for automatically tensioning and taking up the slackof said cable through the action of potential energy, said means beingprovided on said vehicle and comprising self-acting means for stoppingsaid cable and holding it unidirectionally against motion, said lattermeans being adapted to form a stationary fastening means for generating,through blocking of the effective useful length of said cable, atractive reaction force tending to raise said second ramp section intoits outward extended position during the lowering motion through gravityof said innermost ramp section which is constantly suspended from eachone of its own handling cables.
 2. A device according to claim 1,comprising selectively adjustable load transfer means for varying atwill the bearing reaction force of said ramp onto said platform in theworking extended position of the ramp to thereby transfer at least oneselectively variable part of the weight and instant load of said secondramp section to either of said innermost ramp sections and ofindependent auxiliary supporting means provided on said vehicle.
 3. Adevice according to claim 1, wherein said self-acting means forautomatically stopping said handling cables and unidirectionally Holdingsame against motion are arranged so as to be operative only from a givenangle of slope of said innermost ramp section with respect to thevertical direction during the starting period of lowering motionthereof.
 4. A device according to claim 1, wherein each handling cablefor controlling the relative outward extension of said second rampsection is reeved over at least one elevated loose guide pulley mountedon said vehicle and terminates in a movable counterweight forming saidautomatic tensioning and slack taking-up means whereas said automaticmeans for stopping said handling cables and unidirectionally holdingsame against motion consist of a stationary stop means limiting theupward motion of said counterweight provided on said vehicle.
 5. Adevice according to claim 2, wherein each handling cable controlling therelative outward extension of said second ramp section is reeved on atleast one elevated loose guide pulley mounted on said vehicle andterminates into a movable counterweight forming said tensioning andslack taking-up means whereas said automatic means for stopping saidhandling cables and unidirectionally holding same against motion consistof a stationary stop means limiting the upward motion of saidcounterweight and provided on said vehicle, the weight of eachcounterweight being selectively adjustable so that said counterweightforms said load transfer means.
 6. A device according to claim 2,wherein each handling cable controlling the relative outward extensionof said second ramp section is connected to a stationary fastening pointprovided on said vehicle through the medium of an adjusting memberhaving a selectively variable length and forming one aforesaidtensioning and load transfer means.
 7. A device according to claim 2,wherein each handling cable controlling the relative outward extensionof said second ramp section is connected to a linear-displacement typepressure fluid operated actuator generating a selectively adjustableforce and forming one aforesaid tensioning and load transfer means.
 8. Adevice according to claim 1, wherein each handling cable controlling therelative outward extension of said second ramp section is connected to astationary fastening point provided on said vehicle through the mediumof at least one resiliently deformable spring-like member constitutingsaid automatic tensioning and slack taking-up means whereas saidautomatic means for stopping said handling cables and unidirectionallyholding same against motion consist of a stationary stop means limitingthe strain of said spring-like member under maximum stress.
 9. A deviceaccording to claim 1, wherein each cable controlling the relativeoutward extension of said second ramp section is connected to aself-acting winding-up appliance forming said self-acting tensioning andslack taking-up means whereas said automatic means for stopping saidhandling cable and unidirectionally holding samd against motion consistof a stationary fastening means for the end of said cable on saidappliance.
 10. A device according to claim 1, wherein each handlingcable controlling the device outward extension of said second rampsection is connected to an automatic winding-up appliance forming saidself-acting tensioning and slack taking-up means whereas said automaticmeans for stopping said cable and unidirectionally holding same againstmotion consist of braking means for braking said appliance at the end ofthe useful paying out motion.
 11. A device according to claim 2, whereineach handling cable controlling the relative outward extension of saidsecond ramp section is connected to a power-operated winch providing forconstant cable tensioning and which is located on said vehicle to formone aforesaid load transfer means.
 12. A device according to claim 2,wherein said load transfer means consist of at least one counterweighthaving a selectively adjustable weight and located on a lever armintegral with said second ramp section so as to urge the Latter towardsits rasied outward extended position.
 13. A device according to claim 1,comprising a third or outermost ramp section forming a supporting pad tobear on said outside platform and pivotally connected with anintermediate point thereof to the corresponding outer end of said secondramp section forming now an intermediate ramp section, said devicecomprising operated means for raising said outermost ramp section.
 14. Adevice according to claim 13, wherein each handling cable controllingthe extension of said intermediate ramp section is reeved over at leastone associated loose main guide pulley carried by said intermediate rampsection and said cable is secured with its outer end to said outermostramp section at a point located outwards beyond the pivotal connectionof the latter with said intermediate ramp section to form said operatedraising means.
 15. A device according to claim 13, wherein at least oneram-like pressure fluid operated actuator is provided between saidintermedate and outermost ramp sections to form said operated raisingmeans.
 16. A device according to claim 1, wherein one of said first andsecond ramp sections extends beyond its pivotal connection with theother ramp section with at least one longitudinal projecting integralboom carrying towards its free end at least one auxiliary guide pulleyfor each handling cable controlling the relative outward extension ofsaid second ramp section and each cable for operating said first rampsection is reeved over several elevated auxiliary guide pulleys mountedin a same pulley block provided on said vehicle and on a plurality ofmain guide pulleys mounted in a same pulley block carried by saidinnermost or first ramp section, so as to form a reeving whereas eachhandling cable is reeved over several guide pulleys mounted on twopulley blocks, respectively, carried by each projecting boom,respectively, and by said other ramp section so as to form a reeving.17. A device according to claim 16, wherein said second ramp sectionextends beyond its pivotal connection with said innermost or first rampsection with at least one integral projecting longitudinal boom carryingtowards its free end each aforesaid main guide pulley whereas saidinnermost ramp section carries at least one auxiliary guide pulley foreach handling cable controlling the relative outward extension of saidsecond ramp section and leading from each main guide pulley.
 18. Adevice according to claim 1, comprising automatic control means forkeeping said innermost ramp section spaced from said platform in itslowered working position, each handling winch being phase-locked infollow-up relationship to said control means which consist of at leastone sensor member secured to one of said first and second ramp sectionsadjacent to their pivotal connection and adapted to bear upon saidplatform for detecting any variation in the difference between thelevels of said vehicle and said platform.
 19. A device according toclaim 1, comprising automatic control means for adjusting the relativeangular positions of said first and second ramp sections to keep same insubstantially aligned registering relationship or at an optimum slope,each handling winch being phase-locked in follow-up relationship to saidcontrol means which consist of at least one sensor member mounted on oneof said ramp sections in the vicinity of its pivotal connection with theother ramp section, said sensor member being adapted to engage saidother ramp section so as to measure the angle formed therebetween inparticular during any upward motion of said vehicle.
 20. A deviceaccording to claim 7, comprising automatic control means for adjustingthe bearing reaction of said ramp onto said platfrom, each aforesaidload transfer means being phase-locked in follow-up relationship to saidcontrol means which consist of at least one pressured-detecting sensormember mounted on said ramp towards its outer end for bearing upon saidplatform in the working posItion of said ramp and for measuring saidbearing reaction.
 21. A device according to claim 1, comprising push rammeans mounted on said vehicle and adapted to freely engage saidinnermost ramp section in its raised position to initiate its downwardswinging motion through gravity and to brake or slow down its upwardswinging motion at the end thereof, abutment and rest means beingprovided on said vehicle and engageable by said ramp in its raised andstowed position.
 22. A device according to claim 1, wherein saidinnermost ramp section is provided with a pair of side frame members atleast one of which carries a buttressing ram the line of action of whichis spaced from the geometrical axis of pivotal connection between saidadjacent innermost and second ramp sections, said buttressing ram beingadapted to bear removably against an abutment means intergral with thecorresponding side of said adjacent ramp section in the lowered andextended working position of said ramp for blocking said pivotalconnection in the direction of rotation of increasing extension of theramp, in a relative angular position which is selectively variablethrough the adjustable operative length of stroke of said ram, whereasselectively variable connecting means are provided between said sideframe member and said corresponding side, respectively, of both rampsections for blocking said pivotal connection in the direction ofrotation of folding back said ramp, in the same relative angularposition, and wherein on the one hand said ram is of the double-actingkind and pivotally connected with its body onto said side frame memberof said innermost ramp section while extending in substantially parallelrelation to the longtiudinal relative vertical plane of said side framemember, said ram being located higher than the geometrical axis of saidpivotal connection between both ramp sections in their working positionand said adjacent second ramp section also comprising a pair of sideframe members on its opposite sides, respectively, whereas on the otherhand said ram is provided with a movable push head adapted to freely anddirectly engage at least one substantially concave abutment pad formingsaid abutment means and secured to the adjacent end of saidcorresponding side frame member of said second ramp section; operatedlocking means being provided on said corresponding side frame member ofsaid adjacent second ramp section to rigidly connect said movable pushhead with said abutment pad thereby to form said selectively variableconnecting means.
 23. A device according to claim 22, wherein saidmovable push head of said ram comprises at least one sidewise projectingportion adapted to engage said abutment pad; said abutment pad beingsubstantially square shaped and said locking means comprising at leastone movable retaining member actuated by an associated actuator andmounted on said adjacent second ramp section, said retaining memberbeing adapted to bear against said sidewise projecting portion to keepsame in engagement with said abutment pad.
 24. A device according toclaim 23, wherein each retaining member is automatically urgedconstantly towards its operative locking position by a resilient biasingmeans or through gravity so that its associated actuator is only usedfor unlocking purposes.
 25. A device according to claim 22, wherein saidretaining member consists of at least one arm adapted to swing in aplane substantially at right angles to said sidewise projecting portionand to be lowered into engagement with said sidewise projecting portionon that surface portion thereof which is opposite from said abutment padto hold said sidewise projecting portion against motion, said swingingarm being on the other hand adapted to be swung upwards and away fromsaid sidewise projecting portion to release same, said arm beingengageable with said sidewise projecting portion through the tip of itsfree end portion, said tip having a mating shape which is complementaryof that of thE lateral surface of said sidewise projecting portion. 26.A device according to claim 25, wherein said movable push head of saidram comprises a pair of transversely opposite and coaxially alignedthrust pins forming said sidewise projecting portions and adapted toco-operate with a pair of corresponding associated transversely spacedabutment pads whereas said retaining member is a fork-shaped part of thelegs of which form locking arms spaced from each other according to thespacing between said abutment pads, said fork-shaped part beingrotatably mounted on a transverse shaft fitted on said adjacent secondramp section, said fork-shaped part being connected through a radialcrank arm to an auxiliary linear-displacement type pressure fluidoperated actuator mounted on said adjacent second ramp section forrotating said fork-shaped part.
 27. A device according to claim 22,comprising automatic safety means for avoiding any wrong operation andrendering the device fail-safe, said means being mounted on saidadjacent second ramp section and adapted to check and to report therelative position of said locking means at the ends of the locking andunlocking strokes, respectively.
 28. A device according to claim 22,comprising self-acting means for controlling the relative position ofsaid movable push head of said ram, at the end of its stroke, againsteach abutment pad, said means consisting of at least one proximitydetector which is phase-locked in follow-up relationship to meansoperating said locking means.
 29. A device according to claim 22,comprising means for detecting the maximum motion of outward extensionof both aforesaid successive ramp sections into their substantiallyaligned registering position and accordingly the end of maximumretraction stroke of said ram, said ram comprising inner mechanical stopmeans and said detecting means being adapted to discontinue theenergizing of said ram.
 30. A device according to claim 25, comprisingby means for forced guiding of the movable push head of said ram, saidmeans consisting of each sidewise projecting portion which is ofelongated shape so as to project sidewise beyond said associatedabutment pad and engage a guide slot carried by an associated supportingstructure integral with the side frame member of said innermost rampsection.